I've read suggestions on the board that involve using a crate or crates to pass through the fires and jam the gate open.

What if you have no crates? I methodically smashed them all looking for a poison cure potion. If I'd known they'd be needed, I would have kept at least one.

Now I'm stuck. The walkthrough (and the strategy guide) says: "Walk through the Central Fire in front of the Portcullis, and then walk backward through it. After doing that, walk around the edge of the room and 'slip through the gate'" Well, it simply doesn't WORK. I observe that the gate will open briefly when you step through the fire the first time, but then closes right away. Walking BACKWARD through the fire does nothing that I can see. The gate remains closed. If you try to walk around the edge of the room (you get burned twice more) you arrive on the other side of the central fire (in front of the Portcullis) and the door remains closed. What am I missing?

None that I can see. As I said, the book only mentions walking through the fire. But can't you go back to a saved game and then try the other way? Here's what the book says about the Warrior's path (Left Gate)

WARNING SPOILERS FOLLOW>>>>>>>>>>

There's the 2 levers & the Central Healing Fire. But if you use the fire to heal, it resets the room. Avoid the fire, throw the levers and walk out along the sides of the room.

The side you are in is do-able by running through the central fire with a crate (broken or not) in hand and hoping it stops the gate.

If you get as frustrated as I did with it, you can always stack broken crates and climb them to get the other jindol and take the other path where you merely avoid the central fire while you flip the levers on either side.

First, rember to save, save,SAVE.
I took a opend chest. use your strongest person. then I got to the space (I mean space too..not fire..done that too..sigh)saved..again, then ran and jumped to the gate. sometimes it took me a few times to get my timing right, that is why you save before you enter the fire room and again right before the last fire..so you don't have to do all the fires again. FINALY, my timing was right and I kepth the gate open. you know how to carry something, right?
hope this helps a little.
Kathy

One way (in the healing fire side) is to set the respawn rate to high and stand in the healing fire and face the gate. When monsters respawn (skeletons in my case)you can run and push them under the gate to jam it, walk through and then watch the gate crush them to death at your leisure

Instead of faffing around with crates, just line your party up behind the first fire, then RUN straight thru the healing flame and 50% of the time you are quick enough to beat the falling gate (make sure pixies, dwarves or ratlings are in the front)
Si.